In addition to palandio's maps on the previous page, I'd like to list the constituencies with the lowest and highest support for each coalition. Moreover, I'll try to explain why the constituencies voted that way.
Traffic light coalition (SPD + Greens + FDP)Highest percentages:69.3 Hamburg-Eimsbüttel (Hamburg)
67.3 Hamburg-Nord (Hamburg)
67.0 Hamburg-Mitte (Hamburg)
67.0 Stadt Hannover II (Lower Saxony)
66.8 Hamburg-Altona (Hamburg)
66.0 Köln II (North Rhine-Westphalia)
66.0 Oldenburg – Ammerland (Lower Saxony)
65.2 Aurich – Emden (Lower Saxony)
65.2 Stadt Hannover I (Lower Saxony)
64.8 Kiel (Schleswig-Holstein)
Lowest percentages:30.6 Straubing (Bavaria)
30.9 Deggendorf (Bavaria)
31.2 Rottal-Inn (Bavaria)
31.5 Erzgebirgskreis I (Saxony)
31.6 Schwandorf (Bavaria)
31.7 Görlitz (Saxony)
31.9 Bautzen I (Saxony)
32.5 Sächsische Schweiz-Osterzgebirge (Saxony)
34.1 Altötting (Bavaria)
34.7 Mittelsachsen (Saxony)
Comment: Most strongholds of the traffic light coalition are in urban areas. It is especially strong in Hamburg, a city with a large international seaport. Many foreign sailors and businesspeople have been coming to Hamburg for centuries, which is why a liberal "Live and let live" attitude is more prevalent there than in some other German cities. The worst election results for traffic light can be found in rural, socially conservative areas.
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Jamaica coalition (CDU/CSU + Greens + FDP)Highest percentages:65.5 München-Land (Bavaria)
65.4 Köln II (North Rhine-Westphalia)
65.1 Stuttgart I (Baden-Württemberg)
64.3 Düsseldorf I (North Rhine-Westphalia)
64.2 München-Ost (Bavaria)
63.9 München-West/Mitte (Bavaria)
63.8 Münster (North Rhine-Westphalia)
63.5 Starnberg – Landsberg am Lech (Bavaria)
63.3 München-Nord (Bavaria)
62.6 Aachen I (North Rhine-Westphalia)
Lowest percentages:28.5 Elbe-Elster – Oberspreewald-Lausitz II (Brandenburg)
29.1 Suhl – Schmalkalden-Meiningen – Hildburghausen – Sonneberg (Thuringia)
29.9 Prignitz – Ostprignitz-Ruppin – Havelland I (Brandenburg)
29.9 Gotha – Ilm-Kreis (Thuringia)
30.1 Cottbus – Spree-Neiße (Brandenburg)
30.1 Frankfurt (Oder) – Oder-Spree (Brandenburg)
30.3 Saalfeld-Rudolstadt – Saale-Holzland-Kreis – Saale-Orla-Kreis (Thuringia)
30.4 Uckermark – Barnim I (Brandenburg)
30.6 Gera – Greiz – Altenburger Land (Thuringia)
30.9 Mecklenburgische Seenplatte I – Vorpommern-Greifswald II (Mecklenburg-Western Pomerania)
Comment: CDU/CSU, Greens and FDP all do well with high-income voters. Therefore, the Jamaica coalition received the highest vote shares in affluent constituencies. Conversely, constituencies with low support for Jamaica are less affluent (cf.
map of purchasing power in Germany by districts, 2018).
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Red-Red-Green coalition (SPD + Greens + Linke)Highest percentages:74.0 Berlin-Friedrichshain-Kreuzberg – Prenzlauer Berg Ost (Berlin)
65.9 Berlin-Mitte (Berlin)
65.3 Hamburg-Mitte (Hamburg)
64.9 Hamburg-Altona (Hamburg)
64.7 Hamburg-Eimsbüttel (Hamburg)
63.8 Stadt Hannover II (Lower Saxony)
62.2 Berlin-Pankow (Berlin)
61.3 Bremen I (Bremen)
61.0 Köln III (North Rhine-Westphalia)
60.6 Oldenburg – Ammerland (Lower Saxony)
Lowest percentages:23.3 Rottal-Inn (Bavaria)
23.7 Straubing (Bavaria)
24.2 Deggendorf (Bavaria)
25.9 Altötting (Bavaria)
26.3 Schwandorf (Bavaria)
27.9 Donau-Ries (Bavaria)
28.3 Landshut (Bavaria)
28.4 Sächsische Schweiz-Osterzgebirge (Saxony)
28.8 Bautzen I (Saxony)
28.9 Erzgebirgskreis I (Saxony)
Comment: Unsurprisingly, Red-Red-Green is most popular in Germany's most hipsterish constituency. It's interesting to see that some RRG strongholds are also traffic light strongholds. Likewise, Red-Red-Green's weakest results are in rural, socially conservative areas.
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Grand coalition (SPD + CDU/CSU)Highest percentages:64.8 Mittelems (Lower Saxony)
63.9 Unterems (Lower Saxony)
63.8 St. Wendel (Saarland)
63.1 Cloppenburg – Vechta (Lower Saxony)
62.9 Borken II (North Rhine-Westphalia)
62.5 Steinfurt I – Borken I (North Rhine-Westphalia)
62.2 Hochsauerlandkreis (North Rhine-Westphalia)
61.5 Goslar – Northeim – Osterode (Lower Saxony)
61.2 Cuxhaven – Stade II (Lower Saxony)
61.1 Coesfeld – Steinfurt II (North Rhine-Westphalia)
Lowest percentages:26.2 Berlin-Friedrichshain-Kreuzberg – Prenzlauer Berg Ost (Berlin)
30.1 Dresden II – Bautzen II (Saxony)
32.6 Berlin-Mitte (Berlin)
32.6 Sächsische Schweiz-Osterzgebirge (Saxony)
33.7 Berlin-Pankow (Berlin)
34.0 Leipzig II (Saxony)
34.4 Dresden I (Saxony)
35.0 Berlin-Lichtenberg (Berlin)
35.1 Görlitz (Saxony)
35.2 Meißen (Saxony)
Comment: The parties of the grand coalition got their best results in rural constituencies. As many younger people are moving away to the big cities, the rural population has a higher average age. Because older people tend to be more set in their ways, they're more loyal to the parties they're voting for. If someone has been voting CDU/CSU or SPD all their life, they're more likely to continue doing so. The constituencies with the weakest support for the grand coalition can be divided into two groups: The first group is urban constituencies with a very young population. The second group is rural constituencies in the former German Democratic Republic (commonly known as East Germany). Obviously, the AfD greatly cut into the grand coalition's vote share in the east, especially in Saxony. That's partly because the people in the east couldn't participate in democratic elections before 1990, which is why the older people there feel less attached to political parties than their counterparts in the west.